Title:	Far-infrared and Raman spectra of the solid phases of CBOOA
Authors:	Venugopalan, S. Fernandes, J.R. Vani, G.V.
Issue Date:	1975
Publisher:	Gorden and Breach Science Publishers
Citation:	Molecular Crystals and Liquid Crystals, 1975, Vol.31, p29-46
Abstract:	The far-infrared and the Raman spectra of crystalline CBOOA (N-p-cyanobenzilidene-p-n- octyloxyaniline) have been studied above 30 cm-1. The temperature dependence of the far- infrared spectrum reveals the existence of a solid-solid transition at 65 degree C. The two solid modifi- cations can be obtained, respectively, from solvent crystallization (Phase 11) and solidification from the mesophase (Phase I). Differential scanning calorimetric results confirm that an endo- thermic change from Phase II to Phase I occurs at 65 degree C with an associated heat of transition of 2030 cal/mole. X-ray powder diffraction patterns establish that the structures of the two phases are different. Tentative vibrational assignments are made for the far-infrared and the Raman lines observed in the internal mode region. At frequencies below 120 cm-1, both the far-infrared and the Raman spectra of Phase II exhibit distinct modes whereas, Phase I exhibits nearly quasicontinuous spectra. The possible implications of this result for the structure of Phase I and the formation of the mesophase are discussed.
Description:	Restricted Access
URI:	http://hdl.handle.net/2289/2106
ISSN:	1058-725X
Copyright:	1975 Gorden and Breach Science Publishers
Appears in Collections:	Research Papers (SCM)

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